Pump having improved and adjustable packing

ABSTRACT

A reciprocating type pump and method with an improved and customizable approach to varying axial pressure is provided. In one embodiment, a pump may be provided with a pump body, a piston reciprocally moveable within a bore of the pump body in response to a piston drive, and axially spaced apart packing means radially expansible in response to axial pressure exerted on the packing means. A packing nut is also provided, which is disposed at the end of the pump opposite the piston drive for adjustably exerting axial pressure on the packings. Springs may also be provided between the axially spaced apart packing means, which may be used for preloading the packing means and compensating for packing wear, swelling and/or dimensional instabilities.

This application claims the benefit of provisional application Ser. No.61/124,739 to Miroslav Liska, which was filed on 18 Apr. 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an improvement in pumps and more particularlyto those of the reciprocating piston type.

2. Description of the Related Art

Various pumps have been developed over the years for use in dischargingfluid under pressure. Many such pumps produce a discharge of the fluidusing reciprocating movements of a piston in two general directions.Accordingly, an initial suction stroke of the piston inducts fluidthough an inlet opening into one chamber, and a subsequent movement ofthe piston in the opposite direction transfers that liquid into asmaller second chamber and out through a discharge port. In addition toinducting fluid into the first chamber as described above, subsequentstrokes of the piston will decrease the volume of the second chamberforcing fluid in the second chamber out through the discharge port.

Additionally, in many such pumps an expansible packing is provided. Onesuch packing may be provided to surround the piston between the twochambers, and another expansible packing may be provided to surround thepiston rod adjacent the opposite end of the second chamber. Furthermore,in the Wagner pump well known to those in the art, a spring iscompressed between the two packings, which exerts axial pressuresufficient to expand them into sealing engagement with the piston,piston rod, and the surrounding casings. However, the force exerted bysuch a spring is not capable of being altered without disassembly of thepump and replacement of the spring.

It is desirable to be able to alter the force exerted by the spring.This is because the pressure under which liquids or slurries are to bedischarged from such pumps varies depending on the viscosity of theliquid or slurry, the finish to be imparted to the work piece, and otherfactors. To avoid excessive wear on the piston, piston rod, andsurrounding casing, it is desirable to decrease the axial pressureexerted by the spring when low discharge pressures are preferred (as inthe case of relatively thin liquids or slurries), and to increase thepressure when high discharge pressures are preferred (as in the case ofviscous liquids or slurries).

In U.S. Pat. No. 4,775,303 (“the '303 patent”) to the same inventor ofthe present invention, a pump is provided with means for varying thecompression of a spring disposed between the packings. The compressioncan be varied via adjustment of an element with rods and plates, withthe element being accessible exterior to the pump. However, the pump ofthe '303 patent requires standoffs at the upper portion, which areprovided to allow access to an adjustment collar. This results in a pumpthat may be too tall and too large for some applications. In manyapplications, it is desirable to provide a pump that is shorter and morecompact.

SUMMARY OF THE INVENTION

The present invention seeks to provide a reciprocating type pump andmethod with an improved and customizable approach to varying axialpressure, with the pump and method being durable, compact, and utilizingfewer parts than other such pumps known in the art. In at least oneembodiment according to the present invention, a pump is providedcomprising a pump body, a piston reciprocally moveable within a bore ofthe pump body in response to a piston drive, and an axially spaced apartpacking means radially expansible in response to axial pressure exertedon the packing means. A packing nut is also provided, which is disposedat the end of said pump opposite said piston drive for adjustablyexerting axial pressure on the packings.

In another embodiment according to the present invention, a pump systemis provided comprising a pump body, a piston reciprocally moveablewithin a bore of the pump body in response to a piston drive, a drivemotor for providing the piston drive, and axially spaced apart packingmeans radially expansible in response to axial pressure exerted on thepacking means. Springs are also provided, which are disposed between theaxially spaced packing means. Further, a packing nut is disposed at theend of the pump opposite the piston drive for adjustably exerting axialpressure on the packings.

In another embodiment according to the present invention, a method isprovided for a reciprocating pump system. The method comprises providinga pump body, providing a piston reciprocally moveable within a bore ofthe pump body, providing a drive motor for moving the piston, andproviding axially spaced apart packing means that are radiallyexpansible in response to axial pressure, and exerting varying axialpressure on the packing means. Further, a packing nut is disposed at theend of the pump opposite the piston drive, with the axial pressure onthe packings adjustable by tightening or loosening the packing nut.

These and other further features and advantages of the invention will beapparent to those skilled in the art from the following detaileddescription, taken together with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section view of a pump according to oneembodiment of the present invention;

FIG. 2 is a transverse cross-section of the pump in FIG. 1 taken alongsection line 2-2;

FIG. 3 is a detailed transverse view of the piston check valve portionof the pump of FIG. 1;

FIG. 4 is a perspective view of one embodiment of a male adaptoraccording to the present invention;

FIG. 5 is a cross-section view of a male adaptor taken along sectionline 5-5 of FIG. 4;

FIG. 6 is a perspective view of another embodiment of a male adaptoraccording to the present invention;

FIG. 7 is a cross-section view of a male adaptor taken along sectionline 7-7 of FIG. 6;

FIG. 8 is a perspective view of one embodiment of a female adaptoraccording to the present invention;

FIG. 9 is a cross-section view of a female adaptor taken along sectionline 9-9 of FIG. 8;

FIG. 10 is an elevation view of one of the series of rings forming aseal according to one embodiment of the present invention; and

FIG. 11 is a cross-section view of a ring taken along section line 11-11of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

The following description presents several possible embodiments. Thisdescription is not to be taken in a limiting sense, but is made merelyfor the purpose of describing the general principles of the invention,the scope of which is further understood by the appended claims.

The present invention generally provides a reciprocating type pump forthe discharge of a variety of slurries or liquids. This pump, amongother advantages, allows for the axial pressure on various packings tobe easily adjusted such that a variety of slurries or liquids, rangingfrom thin to thick, may more easily pass through the pump mechanism.Other advantages of the adjustable reciprocating pump according to thepresent invention include being: durable, incomplex, compact, externallyadjustable, and customizable to a variety of desired applications.

FIG. 1 shows one embodiment of an improved reciprocating piston typepump 10 according to the present invention. Pump 10 and many of itscomponents are preferably formed from metal, although it is understoodother suitable, durable materials may also be used in accordance withthe present invention. Pump 10 comprises an outer cylindrical pump body12 having a discharge manifold 14 at its upper end. Reciprocallydisposed within the pump body 12 is a piston 16, having an upper end 18projecting from the pump body and including a cross pin 19 forconnecting the piston to a drive motor (not shown).

The lower portion of the piston 16 defines an inlet chamber 20 carryinga first check ball assembly 22 with a check ball 23 as is well known inthe art, which is in communication with a discharge passage 24. Checkball 23 is caged in first check ball assembly 22 for limited movement,and is adjacent to inlet chamber 20. As shown in FIG. 2, a disc-likestructure 25 may be incorporated at the upper end of check ball assembly22 for further limiting the movement of ball 23. Pins (not shown) mayfurther be included within assembly 22 for further caging ball 23 andrestricting its movement. The disc-like structure 25 may also beapertured as at 27. Further, a nut and bolt assembly 29 may befrictionally retained in structure 25, with assembly 29 being adjustableto vary the movement permitted by ball 23.

The cylindrical pump body 12 in FIG. 1 also includes a generallycylindrical inner surface 26 spaced apart radially from an outer surface28 of the piston 16. Disposed within the annular space between the outersurface 28 of the piston 16 and the inner 26 surface of the pump body 12is a piston seal assembly 30 comprising longitudinally spaced apartupper and lower packing means 32, 34. Upper and lower packing means 32,34 comprise, respectively, a series of chevron-shaped packing rings 36,38. The packing means may be comprised of a number of suitablematerials, including various metals, metal alloys, rubber, graphite,plastic, or the like. The upper and lower packing means 32, 34 areseparated by a sleeve 40 having an upper end 42 bearing against thelower extremity of the upper packing means 32 and a lower end 44 bearingagainst the upper extremity of the lower packing means 34. The sleeve 40is slotted so as to permit the passage of fluid from a conduit 46defined by the piston to a conduit 48 defined by the pump body and incommunication with an outlet 50 formed in the discharge manifold 14.

The upper end of the upper packing means 32 is restrained by a femaleadapter 52 fixed within the pump body, and the lower end of 32 or theupper end of packing means 34 may be restrained by a male adapter 53fixed within the pump body. FIGS. 4-7 depict possible embodiments ofmale adapters that may be incorporated into either packing means 32 or34 according to the present invention for aiding in the compression ofthe packing means. The male adapter 80 of FIGS. 4-5 is a simpler annularstructure, with a male end 82 for fitting snugly within the indent ofchevron-shaped packing rings 36, 38. The male adapter 90 of FIGS. 6-7 isalso an annular structure with a male end 92 for fitting with packingrings 36, 38. However, adapter 90 also comprises holes 94, which mayserve a number of functions, including allowing the passage of a liquidor slurry.

FIGS. 8-9 depict one possible embodiment for a female adapter that maybe incorporated into either packings means 32 or 34 according to thepresent invention. The female adapter is used for aiding in thecompression of the packing means. The female adapter 100 is generally anelongated tube structure with female ends 102 for snugly fitting withthe pointed end of one or more of the chevron-shaped packings rings 36,38. While FIGS. 4-9 depict some possible embodiments of male and femaleadapters according to the present invention, it is understood that otherembodiments may also be used within the scope of the present invention.

FIGS. 10-11 depict one embodiment of a packing ring according to thepresent invention. Packing ring 110 has a generally chevron-shaped crosssection 112 as best seen in FIG. 11. The packing ring 110 is designed tobe stackable and/or incorporated with the male and female adapters asdescribed above. The pointed end of the chevron-shaped cross section 112may be fitted into the indented end 116 of another ring 110 or intofemale ends of a female adapter. Likewise, the indented end of thechevron-shaped cross section 112 may be fitted over the pointed end ofanother ring 110 or the male end of a male adapter. Although FIGS. 10-11depict one possible embodiment of a packing ring according to thepresent invention, it is understood that other types of packing ringsmay also be used within the scope of the present invention.

In FIG. 1, a packing nut 54 having an upper end 56 shaped to conformwith the chevron shape of the lower end of the lower packing means 34 isthreadedly received by the pump body 12 at its lower end. It will beseen that tightening of the packing nut 54 advances the packing nutupwardly within the pump body so as to exert an axial pressure on theupper and lower packing means to expand the packing rings into sealingengagement with the outer surface of the piston and the inner surface ofthe pump body. As can also be seen in FIG. 3, the packing nut 54 definesan inlet chamber 58 within which is disposed a second check valveassembly 60 comprising a check ball 62, a seat 64 sealingly engageableby the check ball 62 and a ball cage or retainer 66 for housing thecheck ball and limiting its vertical movement.

The packing nut 54 further includes radially spaced apart recesses 68for receiving an adjustment tool (not shown) for rotating the packingnut as needed to sealingly load the upper and lower packing means. Thepacking nut 54 further includes exterior threads 70 at the lower endthereof for connection to a fluid suction hose (not shown).

Furthermore, compression springs 72, such as Belleville springs, may beincluded as part of the assembly between the packing means 32, 34. Suchsprings provide certain advantages, including but not limited to:preloading of the packing means; compensation for packing ring wear;and, swelling and/or dimensional instabilities.

The pump of the present invention has a number of advantages over otherreciprocal pump type mechanisms. For example, in other similar pumps, anadjustment collar for adjustment of the packing means is located at thetop of the pump assembly. Standoffs were required at the top of the pumpassembly to provide access to the adjustment collar. This arrangementcan take up a great deal of space, making the pump assembly taller andless compact than that of the present invention. By placing the packingnut 54 of the present pump at the lower end of the pump, the necessityof standoffs in the earlier pumps is eliminated. The elimination of thestandoffs and adjustment collar simplifies the adjustment process andresults in a more compact and shorter assembly.

As a result of eliminating such standoffs and an adjustment collar, thenumber of parts needed for an adjustable pump is reduced. The packingnut 54 can advantageously perform a number of functions, including:adjustment of the axially directed sealing forces of the packing means;retention of the lower check ball assembly; and, connection to thesuction hose. Furthermore, the number of seals required has also beenreduced in comparison to prior reciprocal pump assemblies.

In operation, the packing nut 54 is preset by rotating it with respectto the pump body so as to vary the compression of the packing means 32,34 and the springs 72 (if included) according to the magnitude of thepressure under which fluid is to be discharged from the pump. Thecompression of the packing means and springs is increased as thepressure to be developed is increased (such as with thicker liquids orslurries) and/or any adjustment is required due to packing wear. Thecompression of the packings means and springs is decreased when lesspressure is need, such as with thinner liquids or slurries.

During the initial suction stroke of the piston 16, fluid is drawn intothe inlet opening 20, which is immersed in the fluid to be pumped. Then,during the discharge stroke of the piston, the fluid drawn into theinlet through the check assemblies is transferred through the centralpassage 46 of the piston into the discharge passage 24. Thereafter,during suction strokes fluid in the discharge manifold 14 is dischargedthrough the discharge port 50 as fluid is being drawn into the inletopening 20 and during discharge strokes fluid is discharged from insidethe piston 16 through the passage 24 and port 50.

Although the present invention has been described in considerable detailwith reference to certain preferred configurations and methods, otherversions are possible. The invention can be used in many differentapplications. Different materials, configurations, sizes, adaptors,packing ring arrangements and so forth may be used while still adheringto the present reference. Therefore, the spirit and scope of the abovedescription should not be limited to the versions described above.

1. A pump comprising: a pump body; a piston reciprocally moveable withina bore of said pump body in response to a piston drive; axially spacedapart packing means radially expansible in response to axial pressureexerted on said packing means; and a packing nut disposed at the end ofsaid pump opposite said piston drive for adjustably exerting axialpressure on said packings.
 2. The pump of claim 1, further comprisingone or more springs disposed between said axially spaced apart packingmeans.
 3. The pump of claim 1, wherein said pump body further comprisesa discharge manifold at its upper end.
 4. The pump of claim 3, wherein aliquid or slurry enters the pump through an inlet proximate said packingnut and exits said pump through said discharge manifold.
 5. The pump ofclaim 1, wherein the upper end of said piston comprises a cross pin forconnection to a drive motor.
 6. The pump of claim 1, wherein said pistonfurther comprises at least one check valve assembly comprising an inletopening and a discharge opening.
 7. The pump of claim 6, wherein saidcheck valve assembly further comprises a check ball.
 8. The pump ofclaim 1, wherein said pump body further comprises a cylindrical innersurface spaced radially apart from an outer surface of said piston. 9.The pump of claim 8, wherein said packing means are disposed betweensaid inner surface of the pump and said outer surface of said piston.10. The pump of claim 1, wherein said packing means are comprised of oneor more chevron-shaped packing rings, said rings stackable on oneanother.
 11. The pump of claim 1, wherein said packing means comprise anupper portion and a lower portion separated by a sleeve.
 12. The pump ofclaim 1, wherein either end of the packing means may be restrained by afemale or male adapter.
 13. A pump system comprising: a pump body; apiston reciprocally moveable within a bore of said pump body in responseto a piston drive; a drive motor for providing said piston drive;axially spaced apart packing means radially expansible in response toaxial pressure exerted on said packing means; one or more springsdisposed between said axially spaced packing means; and a packing nutdisposed at the end of said pump opposite said piston drive foradjustably exerting axial pressure on said packings.
 14. The pump systemof claim 13, wherein said one or more springs are provided forpreloading said packing means and compensating for packing wear,swelling and/or dimensional instabilities.
 15. The pump system of claim13, wherein said packing nut may be rotatably tightened or loosened tovary the axial pressure of said packing means.
 16. The pump system ofclaim 13, wherein said pump body further comprises a discharge manifoldat its upper end.
 17. The pump system of claim 13, wherein said packingmeans further comprises an inlet chamber, said piston further comprisesat least one check valve assembly and a first conduit, said pump bodyfurther comprises a second conduit in communication with said firstconduit, and said pump body further comprises a discharge manifoldcomprising an outlet.
 18. The pump system of claim 17, wherein a liquidor slurry enters the pump system through said inlet chamber, flowsthrough said at least one check valve assembly into said first conduitand then through said second conduit, and exits said pump system throughsaid outlet.
 19. The pump system of claim 17, wherein said at least onecheck valve assembly further comprises a check ball.
 20. The pump systemof claim 13, wherein said packing means are disposed between an innersurface of said pump and an outer surface of said piston.
 21. The pumpsystem of claim 13, wherein said packing means are comprised of one ormore stackable, chevron-shaped packing rings.
 22. The pump system ofclaim 13, wherein said packing nut comprises one or more recesses forreceiving an adjustment tool for rotating said nut.
 23. A method for areciprocating pump system comprising: providing a pump body; providing apiston reciprocally moveable within a bore of said pump body; providinga drive motor for moving said piston; providing axially spaced apartpacking means that are radially expansible in response to axialpressure, and exerting varying axial pressure on said packing means; andproviding a packing nut disposed at the end of said pump opposite saidpiston drive, adjusting the axial pressure on said packings bytightening or loosening said packing nut.
 24. The method of claim 23,further comprising providing one or more springs between said axiallyspaced packing means, with the springs preloading said packing means andcompensating for packing wear, swelling and/or dimensionalinstabilities.
 25. The method of claim 23, further comprising pumping aliquid through said pump system, such that said liquid is drawn into aninlet of said pump system via a suction stroke, and said liquid istransferred through said piston and out a discharge port via a dischargestroke.